And it shows no signs of abating, with rents in the West's tech hubs expected to be some of the fastest growing across the nation over 2017, according to Zillow's latest forecast.

Millennials are drawn to cities such as Seattle and San Francisco because of job opportunities and high pay, though rental supply remains limited and continues to drive up costs.

While rents in these places are among the fastest risers, there is some good news. The median rent across the US is expected to increase just 1.7% over the next year– a substantial slowdown from the 6% jump in the same period last year.

"Instead of the 10 percent rental appreciation we've been seeing in some places, expect growth more along the lines of 4 to 7 percent," Zillow Chief Economist Svenja Gudell said. "This is still high, but will hopefully give renters some relief."

Here're the top 10 cities with the highest forecasted rent hikes over 2017: